Since aerospike-clj
uses a future based model instead of a callback based model, it is convenient to compose complex asynchronous logic using manifold.
By implementing ClientEvents
2 hooks are exposed that are called for each API call: on-success
and on-failure
.
Those hooks are called with valuable information that can be used, for example to configure automatic logging, or telemtry on your client. Here is an example of a such code, that is reporting useful metrics to statsd. So assuming you have some statsd
namespace tha can connect and report a statsd server, and some metrics
namespace that is used to properly format the metric names:
(ns af-common-rta-aerospike.core
(:require [aerospike-clj.client :as aero]
[statsd.metrics :as metrics]
[statsd.core :as statsd]
[manifold.deferred :as d]))
(defrecord DBMeter []
client/ClientEvents
(on-success [_ op-name op-result _index op-start-time client]
(statsd/send-timing (metrics/format-statsd-metric (:cluster-name client) op-name "latency")
(micros-from op-start-time)
STATSD-RATE)
(statsd/inc-metric (metrics/format-statsd-metric (:cluster-name client) op-name "success"))
(when (= "read" op-name)
(if (some? op-result)
(statsd/inc-metric (metrics/format-statsd-metric (:cluster-name client) "read" "hit"))
(statsd/inc-metric (metrics/format-statsd-metric (:cluster-name client) "read" "miss"))))
op-result)
(on-failure [_ op-name op-ex index op-start-time client]
(statsd/send-timing (metrics/format-statsd-metric (:cluster-name client) op-name "latency")
(micros-from op-start-time)
STATSD-RATE)
(statsd/inc-metric (metrics/format-statsd-metric-fail-aerospike op-ex (:cluster-name client) op-name))
(d/error-deferred op-ex)))
A few notes on the above code:
op-name
, op-result
and index
are strings. They partially used for metrics generation in our case.client
here is the IAerospikeClient
instace. You can use its fields here, or you can even assoc
more keys on it when you create it, to be later used here.op-start-time
is (System/nanoTime)
, converted here to microseconds and used to measure latency.on-success
and on-failure
return the results passed in. Although this logic is the last logic that happens to the operations results (e.g. after trascoders are being run), the returned result will be what the calling code gets as a returned value.Finally, hook it to your client:
user=> (def c (aero/init-simple-aerospike-client ["localhost"] "test" {:client-events (->DBMeter)}))
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